On 4/30 at 11:29am I got an email from OpenSea officially announcing that they are adding support for Polygon (MATIC). Polygon is a network built on top of Ethereum. Interoperability to move NFTs in and out of Polygon into the main blockchain is a key feature for OpenSea.

Support for other blockchains (Polygon (formerly Matic) trading coming soon!)

Look at the trading activity for Polygon (MATIC). it is pretty obvious when the news leaked to the market. 😏